This invention relates generally to the field of drug delivery, and in particular to the pulmonary delivery of powdered medicaments. More specifically, the invention relates to techniques for forming openings in receptacles to facilitate extraction of powdered medicaments from the receptacles during the aerosolizing process.
One promising way to deliver various drugs to a patient is by pulmonary delivery where a drug dispersion or aerosol is inhaled by the patient to permit the active drug within the dispersion to reach the distal or alveolar regions of the lung. Pulmonary drug delivery has shown to be particularly promising because certain drugs have been found to readily absorb within the blood circulation. For example, pulmonary delivery may be a useful approach for proteins and polypeptides that are difficult to deliver by other routes of administration.
A variety of techniques have been employed to deliver drugs to the lungs including liquid nebulizers, metered dose inhalers, and the like. Of particular interest to the invention are dry powder dispersion devices that are able to aerosolize powdered medicaments for inhalation by the patient. Exemplary apparatus for aerosolizing powdered medicaments are described in U.S. Pat. Nos. 5,458,135, 5,775,320, 5,740,794 and 5,785,049, and copending U.S. patent application Ser. No. 09/004,558, filed Jan. 8, 1998, Ser. No. 09/312,434, filed Jun. 4, 1999, 60/136,518, filed May 28, 1999, and 60/141,793, filed Jun. 30, 1999, the complete disclosures of which are herein incorporated by reference.
At least some of the apparatus described in the above references utilize a gas stream to draw the powder into an extraction tube where the powder is deagglomerated, entrained in the gas stream, and exits as an aerosol suitable for inhalation. In some cases, such apparatus may utilize a receptacle that has a penetrable lid. The extraction tube is inserted through the lid and a vent is also formed in the lid. The gas stream then draws air through the receptacle and into the extraction tube. The air drawn through the receptacle extracts the powder where it joins with the gas stream to form the aerosol. It is also possible to extract the powder from within a receptacle by use of a breath actuated device as described in U.S. Patent Application Ser. No. 60/141,793 cited above.
Hence, when utilizing such receptacles to hold the powder, a need exists for creating inlet and outlet openings in the receptacles to facilitate extraction of the powder. The manner in which these openings are created can be challenging. For example, it may be convenient to form such openings while the receptacle is within the aerosolizing apparatus. Due to the relatively small size of such apparatus, the proper formation of appropriately configured holes presents many technical challenges.
Further, in some cases, the openings may need to be precisely located and have a specified size. This can be especially challenging because of the wide variety of cavity shapes. Merely by way of example, copending U.S. Patent Application Ser. No. 60/172,317, filed Dec. 17, 1999, the complete disclosure of which is herein incorporated by reference, describes several shapes of cavities that may be used to hold a powder. Another challenging aspect may be the need to minimize the amount of material that is forced into the cavity during formation of the openings in order to increase the gas flow efficiency through the cavity.
Hence, the invention is related to techniques for forming openings in receptacles to maximize the efficiency with which the powder may be extracted and aerosolized.